subframe is fine, but on/off throttle knocking

[BostonBurley]

I've checked all rear suspension components on both sides, torqued. Rear subframe looks good, no cracks or signs of cracks. Yet when I accelerate HARD, I can hear a "knock" back there. When I let off smoothly there isn't another knock, but if I let off quickly there is a knock like something is hinged and swinging with the inertia. Something heavy enough to make a poignant, deep knock sound. The last time my rear subframe broke (lol) it was repaired by a terrible shop. However, that was 6+ months ago and this sound has begun more recently. For the record I replaced all suspension components and brakes on the car in April...

Am I just not looking hard enough at the rear subframe? Do I seriously need a fourth rear subframe? Might be time for that Taycan order

 

[BostonBurley]

My foot coming off the loud brake aside, this is the knocking I’m hearing.

 

[Hawkjoss]

Did you figured out what was the source of the knock? I have similar issue - knock on acceleration, subframe seems in tact

 

[Aggmeister2010]

Does it do it at all ride heights?

 

[Cheburashka]

Interested to hear the outcome. I would assume it's something in the linkage. I had a similar sound at the SC replaced my upper and lower links, but I also couldn't get my car aligned.

 

[Hawkjoss]

mine is happening on all ride heights. it is easily reproduced - it happens when the load shifts, like something, is moving in the rear of the car back and forth. It is not only the sound, but I can feel something hitting the metal. it happens ONLY on acceleration, it does not knock on when I decelerate, on bumps, turns, etc.
I had 3(!) visits to the SC where they kept a car for a few days each time, but they can't find the source of the problem. This issue began when the Drive Unit was replaced. I thought it might be a cracked subframe, but the SC said the subframe is fine. I spent almost 2 hrs myself looking at all linkages/subframe/motor mounts etc and can;t find anything too ;-(

 

[Aggmeister2010]

mine is happening on all ride heights. it is easily reproduced - it happens when the load shifts, like something, is moving in the rear of the car back and forth. It is not only the sound, but I can feel something hitting the metal. it happens ONLY on acceleration, it does not knock on when I decelerate, on bumps, turns, etc.
I had 3(!) visits to the SC where they kept a car for a few days each time, but they can't find the source of the problem. This issue began when the Drive Unit was replaced. I thought it might be a cracked subframe, but the SC said the subframe is fine. I spent almost 2 hrs myself looking at all linkages/subframe/motor mounts etc and can;t find anything too ;-(

Have you tried putting the seats down and having a friend crawl around the back to at least see if there's an "area" of the back that it's coming from?

 

[Hawkjoss]

not yet, but planned to do it. it seems like it is coming from the driver's side, but sometimes I can hear it from center/passenger side too. it is ALWAYS one distinct clunk/knock. will record the video soon ( planning to set up GoPro on the subframe - maybe that will make it more clear )

 

[Hawkjoss]

Update - 4th visit to SC didn’t fix anything, they can’t find a source of the knock.
Any advice on reputable mechanics in DMV(ideally Ashburn) area?